This two-digit digital pressure gauge was found in the 1992 special edition of Radio Electronics Experimenter. A/D converter integrated circuits are uncommon today.
Found in a 1980s documentation, this amplifier uses an integrated circuit of the era. The RLC...
This circuit produces a voltage drop in the first pulse, turning off the relay. On the second...
Operational amplifiers or comparators like those in the LM139 series can be used on this circuit,...